I've got a bunch of these Ultra 5s to put Gentoo on. They can be a pain to get to boot right, but once they do you're good to go. As suggested before, try to burn the cd at a slower speed. Other than that, just keep trying until you get it. Sometimes I have to "boot cdrom" 5 times before it'll actually do it. Also, trying the 2004.0 cd has worked for me in situations where the 2004.1 wouldn't.

Other than that, Gentoo goes on like a charm. I do a stage2 build on these but I'm sure a stage3 or stage1 would work. Takes about a day to "emerge system" on them. And about an hour to do the kernel. But once they're running they're not too sluggish. X.org works great with full 1024x768.

I just did an stage 1 on an Ultra 5 with 128 megs of ram and it went perfectly.
Also, I recieved the same illegal instruction error as you did while attempted to boot from the 2004.1 live cd. I tried the cd image from gustavoz, however, and it booted fine. I believe the only difference is a slightly older version of silo:

I guess its realy that silo-1.4.4 thing,
I tried it on a Sparc-Station 4, never runs, forget it....
I tried it on a Sparc-Classic, never runs, forget it.....
I tried it on a Ultra 5, never runs, forget it....
I tried it with 2004.0, runs, yes, on all a.m. boxes.
So, whats the point ?
Rel. 2004.1 is for a couple of maschines a waste of CD-ROMS, a waste of time, a waste of bandwith.
So, if possible, mark the liveCD as buggy. Add a text on the directory with a warning.
Don't missunderstand me, I'm realy a great fan of Gentoo, I use it on 2 PowerMacs, 2 SunBoxes (the ultra 5 is a box i got today, and I tried all the tipps, as try it 5 times (or more), burn it with 4x)
At the end, its silo 144, it is, sorry to be so harsh, unusable.
To use that version on 2004.1 make it unusable.
Hopefully silo 1.4.5 would be better and find (it it is better) its way to the next LiveCDs ( I guess 2004.2).

Sorry, sometimes not amused as I spend some CD-Roms, some useless time on it, OK, take it as a test-response for 2004.1

BTW: 2004.0 runs perfect....on this ultra 5
To use this instead of 2004.1 solved it.
But I also like to try the 2004.1 with silo 132, as a.m.

Realy, this silo 1.4.4 thing is the damon to drive you crazy....

cheers,
Frank_________________always look at yellow site of Linux on the PPC.
Its PPCNUX.

A local colorado guy! I have Ultra Sparc 5. hda is a 120GB Solaris 9 partition. hdd is a 120GB Gentoo partition. I use 'boot' for solaris, and boot disk2 for Gentoo. When I ok> boot disk2, it goes into SILO and immedialtely starts to boot gentoo.

I do have /boot on hdd slice 1, and / on hdd slice 1. Documentation had mixed notes, but I think I could get away with just /. Not sure if that is associated with my problem.

I have verified that silo.conf points to hdd. You may be correct on the 2nd one? Ideas on how to resolve that? Do I need a sun disklabel if there is no sun partition on hdd? I have tried the boot: /boot/kernel-2.4.27 from silo and it takes off, but I get the same error. So it looks like silo is on the correct disk, and the disk is mounted, but my kernel wants the hda.